Changes in the structure of tethered chain molecules as predicted by density functional approach

Abstract

We use a version of the density functional theory to study the changes in the height of the tethered layer of chains built of jointed spherical segments with the change of the length and surface density of chains. For the model in which the interactions between segments and solvent molecules are the same as between solvent molecules we have discovered two effects that have not been observed in previous studies. Under certain conditions and for low surface concentrations of the chains, the height of the pinned layer may attain a minimum. Moreover, for some systems we observe that when the temperature increases, the height of the layer of chains may decrease.

A density functional study of the structure of tethered chains in a binary mixture

“…In the previous paper [50] we have studied the changes in the structure of tethered chains in contact with a one-component fluid. We have shown that in the region of mediate grafting coverages, a minimum on the curve ln(h) vs ln(ρ * c ) can develop.…”

“…In our previous paper [50] the effect of strong adsorption of one-component fluid on the height of the bonded layer has been investigated. In this work we employ the density functional theory to describe the short grafted chains immersed by a mixture of two liquids.…”

Adsorption on Ligand-Tethered Nanoparticles

“…In this case, the grafted chains did not practically affect one another, and they assumed unperturbed configurations. For medium-covered substrates, the height fell to a minimum [62]. With a further increase of the grafting density, the brush height increases as in the predicted scaling theories [19].…”

“…Such a relation accurately approximates the data obtained for dense brushes. However, density functional studies [62] showed that the behavior of sparse brushes can be completely different. For very low surface densities of tethered chains, the brush height remained almost constant.…”

“…The effect of the adsorption of particles on the brush height was much less studied. We analyzed the impact of the fluid density on the brush height using density functional theory [62,63]. Increasing ρ b can both increase or decrease the brush height.…”